Green River Blues

The Green River Formation of Wyoming, USA, is familiar to geologists not only for its well-preserved fossils but also because it has come to the forefront of debate on the age of the earth.

Critics of creationism have frequently appealed to the Green River
Formation as irrefutable evidence for a multi-million-year-old
earth.1,2,3

The reason is that the deposit is said to consist of several
million thin layers of shale, each of which is said to represent a
single season‘s deposition in an ancient lake (the coarser layers in
the summer, and the finer layers in the winter). Each summer/winter
pair of layers — called varves — would thus represent a single year.
Most geologists claim that this formation alone must have taken
several million years to be laid down. Old-earth geologist (and
professing evangelical) Dr Davis Young put it like this:

‘There are more than a million vertically
superimposed varve pairs in some parts of the Green River Formation.
These varve deposits are almost certainly fossil lake-bottom
sediments. If so, each pair of sediment layers represents an annual
deposit . . . . The total number of varve pairs indicates that the
lakes existed for a few million
years.‘
4

Obviously, this is a serious challenge to those who believe in a
young age for the earth as indicated by Scripture (less than 10,000
years).

However, the critics (who in any case err by relying on the
incomplete data of fallible scientists, rather than the infallible
God who knows all data) leave out some vital information that sheds
light on the origin of ‘varves’. As long ago as 1961, creationists
were pointing out features of the Green River Formation that were
difficult to reconcile with the conventional varve
interpretation.5 For
instance, well-preserved fossils are abundant and widespread
throughout the sediments. According to two conventional geologists:

‘. . . fossil catfish are distributed in the
Green River basin over an area of 16,000
km6
. . . The catfish range in length from 11 to 24 cm, with a mean of 18
cm. Preservation is excellent. In some specimens, even the skin and
other soft parts, including the adipose fin, are well
preserved.’7

Another evolutionist stated:

‘During the early to mid-1970s enormous
concentrations of
Presbyornis
[an extinct shorebird] have been
discovered in the Green River
Formation.’8

This should tell us that the Green River Formation is no ordinary
lake deposit! Modern-day lakes do not provide the conditions needed
for the preservation of abundant fossil fish and birds.

Experiments by scientists from the Chicago Natural History Museum
have shown that fish carcasses lowered on to the muddy bottom of a
marsh decay quite rapidly, even in oxygen-poor conditions. In these
experiments, fish were placed in wire cages to protect them from
scavengers, yet after only six-and-a-half days all the flesh had
decayed and even the bones had become
disconnected.9

The Presbyornis fossils are even more problematic. Birds
have hollow bones that tend not to preserve well in the fossil
record. How were these bird bones protected from scavenging and decay
for thousands of years until a sufficient number of the fine annual
layers had built up to bury them? ‘Enormous concentrations’ of bird
bones are a clear indication that something is seriously wrong with
the idea of slow accumulation. Instead, such fossils support the
notion of rapid burial.

Creationist suspicions about the validity of the varve
interpretation were confirmed in a study by two geologists published
in 1988.10 Near Kemmerer
in Wyoming the Green River Formation contains two volcanic ash (tuff)
layers, each about two to three centimetres thick.

A volcanic ash layer is an example of what geologists call an ‘event horizon’, because it is laid down essentially instantaneously
by a single event, in this case a volcanic eruption. The two ash
layers are separated by between 8.3 and 22.6 centimetres of shale
layers.

If the standard interpretation is correct, then the number of
shale layers between the ash layers should be the same throughout the
Green River basin, since the number of years between the two
eruptions would be the same.

However, the geologists found that the number of shale layers
between the ash beds varied from 1160 to 1568, with the number of
layers increasing by up to 35% from the basin centre to the basin
margin! The investigators concluded that this was inconsistent with
the idea of seasonal ‘varve’ deposition in a stagnant lake.

So how were the great thicknesses of finely laminated shale in the
Green River Formation laid down? Creationist geologists need to
investigate the issue more closely, but there seems to be great
potential for developing a catastrophic model for the origin of these
sediments. There is a large body of experimental and observational
data that shows that varve-like sediments can build up very rapidly
under catastrophic
conditions.11,12,13,14,15
For instance, in 1960 Hurricane Donna struck the coast of southern
Florida and deposited a blanket of thinly-laminated lime-mud six
inches thick.16
Another example comes from a Swiss lake, in which up to five pairs of
layers were found to build up in a single year, deposited by rapid
underflows of turbid
water.17

Given the right conditions, thinly-laminated muddy sediments can
and do form by rapid sedimentation. Contrary to claims by old-earth
proponents, long periods of time are not demanded.

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Answers in Genesis is an apologetics ministry, dedicated to helping Christians defend their faith and proclaim the gospel of Jesus Christ effectively. We focus on providing answers to questions about the Bible—particularly the book of Genesis—regarding key issues such as creation, evolution, science, and the age of the earth.